Microlithographic projection exposure apparatus are used to manufacture microstructured components such as for example integrated circuits or LCD's. A projection exposure apparatus of this kind includes an illumination device and a projection objective. In the microlithography process the image of a mask (also referred to as reticle) that is illuminated by the illumination device is projected via the projection objective onto a substrate (for example a silicon wafer) that is coated with a light-sensitive coating (photoresist) and arranged in the image plane of the projection objective, in order to transfer the mask structure onto the light-sensitive coating.